(1) Be able to create two different stackable items; this usually means the earliest you can do this is when you are in the middle of Chapter 3, where you have the blueprints for the Deo Bomb and Molotov.

(2) Possess the crafting components and cash to create at least one unit of those items.

(3) You must also possess two or more of the stackable item you wish to duplicate.

Once you have, you will now proceed to the next step.

(4) On your toolbelt (equipped item/weapon ring), occupy all usable slots that are not the two items -- the one being duplicated, and the one being created on the workbench. You may use any hand weapon, firearm, or other stackable item to fulfill this condition.

(5) Make sure you have at least one empty slot in the (paused) inventory.

(6) Equip the stackable item in your character's hand and use the workbench.

(7) Create any stackable item that is not in your current toolbelt (equipment ring). Note, you may duplicate alcohol and use the Molotov blueprint to create an infinite loop ...

If you successfully met all these conditions and followed the instructions correctly, you will have a new "stack" of your items in hand on your toolbelt; the stack you held before you did this exploit will be moved to your paused inventory. You may de-equip your new stack of items and it will combine with any similar stack of items until it reaches the cap of 30 units.

Using this exploit, you may duplicate the following stackable items (e.g., all of them) as long as you can equip them on your toolbelt: